Aqueous bleaching agents

ABSTRACT

The invention concerns novel aqueous bleaching agents containing--relative to the agents--between 1.0 and 10.0 wt % alkali hypochlorite, between 0.5 and 1.5 wt % alkali hydroxide, between 0.5 and 2.0 wt % silicates, between 0.01 and 1.0 wt % phosphonic acids and/or phosphonates, and between 0.01 and 1.0 wt % polyacrylic acid compounds as well as optionally other conventional additives and auxiliary materials. The agents can be formulated without turbidity and reliably protect the textiles treated therewith against encrustation and yellowing, even in the presence of water hardness and heavy metal ions.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to new aqueous bleaching compositions containingalkali metal hypochlorites, alkali metal hydroxides and a ternaryinhibitor system and to the use of the ternary mixture as anincrustation and yellowing inhibitor for the production of aqueousbleaching compositions.

2. Discussion of Relative Art

Whereas powder-form or liquid heavy-duty detergents which only developtheir cleaning performance at relatively high temperatures are used inmany European countries for washing heavily soiled textiles, consumersin the USA and Spain, for example, preferred cold washing where a liquidbleach, preferably based on hypochlorite, is added in addition to adetergent in order to remove particularly difficult stains.

Numerous liquid bleaching compositions are known from the prior art.Thus, EP-A 0 274 885 (ICI), for example, recommends the use of mixturesof linear and branched amine oxides for the production of viscoushypochlorite bleaches. According to the teaching of EP-A 0 145 084(Unilever), mixtures of amine oxides with soaps, sarcosinates, tauridesor sugar esters may also be used for this purpose. The use of amineoxides with soap or sarcosinate and other anionic surfactants, forexample alkyl sulfates, alkyl ether sulfates, secondary alkanesulfonates or alkyl benzenesulfonates, as thickening component forhypochlorite solutions is known from EP-A 0 137 551 and EP-A 0 447 261(Unilever). EP-A 0 156 438 reports on the use of alkylaryl sulfonates asthickeners in aqueous bleaching compositions which contain certainstilbene dyes as optical brighteners. ES-A 8801389 (Henkel Iberica)relates to bleaching compositions based on aqueous hypochloritesolutions which predominantly contain alkyl ether sulfates and, inaddition, small amounts of amine oxides as surfactant component. Inaddition, aqueous bleaching compositions containing sodium hypochloriteand anionic surfactants are known from EP-A1 0 447 261. However, thehypochlorite concentration of these compositions is between 0.1 and 8%by weight and preferably between 0.5 and 5% by weight of activechlorine. In German patent DE-C1 4 333 100, applicants propose aqueousbleaching and cleaning compositions based on hypochlorites, fattyalcohol ether sulfates, amine oxides and amine oxide phosphonic acids.

International patent applications WO 94/10272, WO 95/03383, WO 95/08610and WO 95/08611 (Procter & Gamble) relate to hypochlorite-containingbleaching compositions containing short-chain anionic surfactants suchas, for example, octyl sulfate. European patent application EP-A 0 688857 (Procter & Gamble) describes hypochlorite-containing bleachingcompositions containing periodates and carbonates for adjusting the pHvalue. European patent application EP-A 0 688 345 (Procter & Gamble)relates to hypochlorite-based bleaching compositions containing smallquantities of silicates and/or carbonates, polycarboxylates and radicalscavengers. An alkaline hypochlorite-based bleaching compositioncontaining carbonates and silicates for stabilizing perfume oils is alsoproposed in European patent application EP-A 0 622 451 (Procter &Gamble).

Bleaching compositions of the type mentioned above are expected tosatisfy stringent consumer requirements. They have to belaundry-compatible, i.e. the treatment with the basically aggressivechemical hypochlorite is expected to remove stains without affecting thefabric. Since skin contact with the bleaching compositions cannot beruled out, the compositions are also expected to be as dermatologicallysafe as possible. In cases where hard water is used for the washingprocess, there is the problem of lime deposits on the fibers and hencethe danger of fabric incrustation, especially in the event of prolongedexposure to the composition. Another problem is that hypochloritesolutions also attack metals and the traces of metals dissolved in thisway can be deposited on the textile fibers during the washing processwhich is ultimately reflected in yellowing of the fabric.

Accordingly, the complex problem addressed by the present invention wasto provide storage-stable, non-clouding aqueous bleaching compositionswhich, at one and the same time, would be chlorine-stable,laundry-compatible and dermatologically safe, would have a sufficientlyhigh viscosity and, for a high stain removing power, would reliablyprevent the deposition of lime and metal traces on the fabrics.

DESCRIPTION OF THE INVENTION

The present invention relates to aqueous bleaching compositionscontaining--based on the composition--

1.0 to 10.0% by weight of alkali metal hypochlorite

0.5 to 1.5% by weight of alkali metal hydroxide

0.5 to 2.0% by weight of silicates

0.01 to 1.0% by weight of phosphonic acids and/or phosphonates and

0.01 to 1.0% by weight of polyacrylic acid compounds

and optionally other typical auxiliaries and additives.

It has surprisingly been found that the addition of an inhibitor mixtureconsisting of defined quantities of silicates, phosphonic acids orphosphonates and polyacrylates to the alkaline hypochlorite solutionsboth significantly reduces the deposition of lime and metals on thefabrics during washing and hence counteracts incrustation and yellowingof the fibers and also enables non-clouding and storage-stablecompositions to be formulated. The protection which the new compositionsafford against incrustation and corrosion is clearly apparent above allin the event of long exposure times. The invention includes theobservation that the additional use of mild chlorine-stable surfactants,such as--preferably--alkyl ether sulfates, amine oxides, alkyl and/oralkenyl oligoglycosides and fatty acid salts, leads to a furtherimprovement in cleaning performance and dermatological compatibility.Finally, the compositions according to the invention have a sufficientlyhigh viscosity so that they can readily be dosed by the consumer.

Alkali Metal Hypochlorites and Alkali Metal Hydroxides

Alkali metal hypochlorites in the context of the invention areunderstood to be lithium, potassium and--in particular--sodiumhypochlorite. The hypochlorites may be used in quantities of preferably3.0 to 7.0% by weight and, more preferably, 4 to 6% by weight, based onthe composition. Alkali metal hydroxides are understood to be sodiumand/or potassium hydroxide which are used in quantities of preferably0.7 to 1.2% by weight, based on the composition.

Silicates

Silicates which may be used for the purposes of the invention areunderstood to include salts and esters of orthosilicic acid Si(OH)₄ andself-condensation products thereof. Accordingly, the followingcrystalline materials, for example, may be used as silicates:

(a) neosilicates (island silicates) such as, for example, phenakite,olivine and zirconium;

(b) sorosilicates (group silicates) such as, for example, thortveititeand hemimorphite;

(c) cyclosilicates (ring silicates) such as, for example, benitoite,axinite, beryllium, milarite, osumilite or eudialyte;

(d) inosilicates (chain and band silicates) such as, for examplemetasilicates (for example diopside) or amphiboles (for exampletremolite);

(e) phyllosilicates (laminar and layer silicates) such as, for example,talcum, kaolinite or mica (for example muscovite);

(f) tectosilicates (skeletal silicates) such as, for example feldsparsand zeolites and also clathrasils or dodecasils (for examplemelanophlogite), thaumasite and neptunite.

In contrast to the ordered crystalline silicates, silicate glasses, forexample soda or potash waterglass, are preferably used. They may be ofnatural origin (for example montmorillonite) or may be synthesized.Another embodiment of the invention is characterized by the use ofalumosilicates. Typical examples of alkali metal or alkaline earth metalsilicates are sodium and/or potassium silicates with a modulus of 1.0 to3.0 and preferably 1.5 to 2.0. The silicates are normally used inquantities of 0.8 to 1.2% by weight, based on the composition.

Phosphonic Acids and Phosphonates

Phosphonic acids in the context of the invention are understood to beorganic derivatives of the acid HP(O)(OH)₂ ; phosphonates are the saltsand esters of these phosphonic acids. The organic phosphonic acids orphosphonates preferably used for the purposes of the invention are knownchemical compounds which may be prepared, for example, by theMichaelis-Arbuzov reaction. They correspond to formula (I): ##STR1## inwhich R¹ is an optionally functionalized alkyl and/or alkenyl groupcontaining 1 to 22 carbon atoms, preferably 2 to 18 carbon atoms andmore preferably 6 to 12 carbon atoms and R² is hydrogen, an alkali metaland/or alkaline earth metal, ammonium, alkylammonium and/oralkanol-ammonium or an optionally functionalized alkyl and/or alkenylradical containing 1 to 22, preferably 2 to 18 and more preferably 6 to12 carbon atoms. Typical examples are optionally hydroxy-, nitrilo-and/or amino-substituted phosphonic acids such as, for example, ethylphosphonic acid, nitrilotris(methylene phosphonic acid), 1-amino- or1-hydroxyalkane-1,1-diphosphonic acids. A preferred embodiment of theinvention is characterized by the use of amine oxide phosphonic acidswhich correspond to formula (II): ##STR2## where R³ is hydrogen, a(CH₂)_(m) (CHCH₃)_(n) NH₂ O group or an alkali metal, m is a number of 1to 4 and n is 0 or 1. Amine oxide phosphonic acids are builders orsequestering agents which are marketed, for example, by Bozetto, Italy,under the name of SEQUION®. They are produced by reactingaminophosphonic acids to form the amine oxide. Both mono- and diamineoxides in the form of the phosphonic acids or salts corresponding toformula (II) may be used for the purposes of the invention. Amine oxidephosphonic acids in which R³ is hydrogen, m is 3 and n is 0 (amine oxidebased on aminotrimethylene phosphonic acid) are preferably used. Thephosphonic acids or phosphonates are normally used in quantities of 0.3to 0.7% by weight, based on the composition.

Polyacrylic Acid Compounds

Polyacrylic acid compounds in the context of the invention arepreferably homopolymers of acrylic acid and methacrylic acid or estersthereof. Besides the acids, esters of the acids with alcohols containing1 to 4 carbon atoms can also be polymerized. Polyacrylic acid compoundswith a particularly advantageous stabilizing effect are present asalkali metal salts and have an average molecular weight in the rangefrom 1,000 to 10,000 and more particularly in the range from 4,000 to6,000 dalton. They are preferably used in quantities of 0.02 to 0.05% byweight.

Alkyl Ether Sulfates

The compositions according to the invention may contain as furthercomponents surfactants of the alkyl ether sulfate type which may beobtained by sulfation of alkyl polyglycol ethers and subsequentneutralization. The alkyl ether sulfates suitable for the purposes ofthe invention correspond to formula (III):

    R.sup.4 O--(CH.sub.2 CH.sub.2 O).sub.n SO.sub.3 X          (III)

where R⁴ is an alkyl group containing 12 to 18 and, more particularly,12 to 14 carbon atoms, n is a number of 2 to 5 and, more particularly, 2to 3 and X is sodium or potassium. Typical examples are the sodium saltsof sulfates of the C_(12/14) cocoalcohol+2, +2.3 and +3 EO adduct. Thealkyl ether sulfates may have a conventional or narrow homologdistribution. The alkyl ether sulfates are used in quantities ofpreferably 1 to 8% by weight, more preferably 1.5 to 6% by weight andmost preferably 2 to 4% by weight, based on the composition.

Amine Oxides

Amine oxides are also known substances which are occasionally classed ascationic surfactants, but generally as nonionic surfactants. They areproduced from tertiary fatty amines which normally have one long and twoshort or two long and one short alkyl chain by oxidation in the presenceof hydrogen peroxide. The amine oxides suitable as surface-activeingredients for the purposes of the invention correspond to formula(IV): ##STR3## in which R⁵ is a linear or branched alkyl groupcontaining 12 to 18 carbon atoms and R⁶ and R⁷ independently of oneanother have the same meaning as R⁵ or represent an optionallyhydroxy-substituted alkyl group containing 1 to 4 carbon atoms. Amineoxides corresponding to formula (IV), in which R⁵ and R⁶ representC_(12/14) or C_(12/18) cocoalkyl radicals and R⁷ is a methyl group or ahydroxyethyl group, are preferably used. Amine oxides corresponding toformula (IV), in which R⁵ is a C_(12/14) or C_(12/18) cocoalkyl groupand R⁶ and R⁷ represent a methyl or hydroxyethyl group, are alsopreferred. The amine oxides are preferably used in quantities of 1.5 to6% by weight and more preferably in quantities of 2 to 4% by weight,based on the composition.

Alkyl and/or Alkenyl Oligoglycosides

Alkyl and alkenyl oligoglycosides are known nonionic surfactants whichcorrespond to formula (V):

    R.sup.8 O--[G].sub.p                                       (V)

where R⁸ is an alkyl and/or alkenyl radical containing 4 to 22 carbonatoms, G is a sugar unit containing 5 or 6 carbon atoms and p is anumber of 1 to 10. The alkyl and/or alkenyl oligoglycosides alsosuitable as surface-active ingredients may be derived from aldoses orketoses containing 5 or 6 carbon atoms, preferably glucose. Accordingly,the preferred alkyl and/or alkenyl oligoglycosides are alkyl and/oralkenyl oligoglucosides. The index p in general formula (V) indicatesthe degree of oligomerization (DP), i.e. the distribution of mono- andoligoglycosides, and is a number of 1 to 10. Whereas p in a givencompound must always be an integer and, above all, may assume a value of1 to 6, the value p for a certain alkyl oligoglycoside is ananalytically determined calculated quantity which is generally a brokennumber. Alkyl and/or alkenyl oligoglycosides having an average degree ofoligomerization p of 1.1 to 3.0 are preferably used. Alkyl and/oralkenyl oligoglycosides having a degree of oligomerization of less than1.7 and, more particularly, between 1.2 and 1.4 are preferred from theapplicational point of view. The alkyl or alkenyl radical R⁸ may bederived from primary alcohols containing 4 to 11 and preferably 8 to 10carbon atoms. Typical examples are butanol, caproic alcohol, caprylicalcohol, capric alcohol and undecyl alcohol and the technical mixturesthereof obtained, for example, in the hydrogenation of technical fattyacid methyl esters or in the hydrogenation of aldehydes from Roelen'soxosynthesis. Alkyl oligoglucosides having a chain length of C₈ to C₁₀(DP=1 to 3), which are obtained as first runnings in the separation oftechnical C₈₋₁₈ coconut oil fatty alcohol by distillation and which maycontain less than 6% by weight of C₁₂ alcohol as an impurity, and alsoalkyl oligoglucosides based on technical C_(9/11) oxoalcohols (DP=1 to3) are preferred. In addition, the alkyl or alkenyl radical R⁸ may alsobe derived from primary alcohols containing 12 to 22 and preferably 12to 14 carbon atoms. Typical examples are lauryl alcohol, myristylalcohol, cetyl alcohol, palmitoleyl alcohol, stearyl alcohol, isostearylalcohol, oleyl alcohol, elaidyl alcohol, petroselinyl alcohol, arachylalcohol, gadoleyl alcohol, behenyl alcohol, erucyl alcohol, brassidylalcohol and technical mixtures thereof which may be obtained asdescribed above. Alkyl oligoglucosides based on hydrogenated C_(12/14)coconut oil fatty alcohol having a DP of 1 to 3 are preferred. Theglycosides are used in quantities of preferably 1.5 to 6% by weight andmore preferably 2 to 4% by weight, based on the composition.

Fatty Acid Salts

The compositions according to the invention may contain as furthersurfactants fatty acid salts corresponding to formula (VI):

    R.sup.9 CO--OX                                             (VI)

in which R⁹ CO is an acyl group containing 12 to 22 carbon atoms and Xis an alkali metal. Typical examples are the sodium and/or potassiumsalts of lauric acid, myristic acid, palmitic acid, palmitoleic acid,stearic acid, isostearic acid, oleic acid, elaidic acid, petroselicacid, linoleic acid, linolenic acid, elaeostearic acid, arachic acid,gadoleic acid, behenic acid and erucic acid and the technical mixturesthereof obtained in the pressure hydrolysis of technical fats and oils.Salts of technical cocofatty acid or tallow fatty acid are preferablyused. Since the formulations according to the invention are highlyalkalized, the salts may also be replaced by the fatty acids which areneutralized in situ on introduction into the mixture. Those compositionsaccording to the invention which are required to be particularlylow-foaming preferably contain fatty acid salts as an optionalcomponent. The soaps are preferably used in quantities of 1.5 to 6% byweight and more preferably in quantities of 2 to 4% by weight, based onthe composition.

COMMERCIAL APPLICATIONS

The compositions according to the invention generally have a non-aqueouscomponent of 5 to 35 and preferably 8 to 15% by weight and are suitablefor the treatment of textile materials such as, for example, yarns, websand, in particular, textiles. They are normally used at lowtemperatures, i.e. in cold washing (ca. 15 to 25° C.). The compositionsare not only distinguished by excellent stain removal, they alsoreliably prevent the deposition of lime and metal traces on the fibersand, in doing so, also prevent incrustation and yellowing. Although theactual use of the compositions is directed to the removal of stainsduring the washing process, the compositions are also basically suitablefor other applications where hypochlorite solutions are used, forexample the cleaning and disinfection of hard surfaces.

Suitable other auxiliaries and additives are, for example, otherchlorine-stable surfactants and hydrotropes such as, for example, alkylsulfates, alkyl sulfonates, alkyl benzenesulfonates, xylenesulfonates,sarcosinates, taurides, isethionates, sulfosuccinates, betaines, sugaresters, fatty alcohol polyglycol ethers and fatty acid-N-alkylglucamides. The sum total of all surfactants, based on the compositions,is preferably 1 to 15% by weight and more preferably 5 to 10% by weight.The compositions according to the invention generally have a pH value of12.5 to 14.

In addition, the compositions may contain active-chlorine-stablefragrances, optical brighteners, dyes and pigments in a total quantityof 0.01 to 0.5% by weight, based on the composition. Known fragrancesresistant to active chlorine include, for example, monocyclic andbicyclic monoterpene alcohols and esters thereof with acetic orpropionic acid (for example isoborneal, dihydroterpineol, isobornylacetate, dihydroterpenyl acetate). The optical brightener may be, forexample, the potassium salt of4,4'-bis-(1,2,3-triazolyl)-(2-)-stilbene-2,2-sulfonic acid which ismarketed under the name of Phorwite® BHC 766. Suitable pigments areinter alia green chlorophthalocyanines (Pigmosol® Green, Hostaphine®Green) or yellow Solar Yellow BG 300 (Sandoz). The compositionsaccording to the invention are produced by stirring. The productobtained may optionally be decanted or filtered to remove foreign matterand/or agglomerates. In addition, the compositions have a viscosityabove 100 mPas, as measured at 20° C. in a Brookfield viscosimeter.

The present invention also relates to the use of mixtures consisting of

(a) silicates,

(b) phosphonic acids and/or phosphates and

(c) polyacrylic acid compounds

as incrustation and yellowing inhibitors for the production of aqueousbleaching compositions. The mixtures may contain the components in aratio by weight of (a) to (b) to (c) of (10 to 50):(5 to 25):(10 to 50),with the proviso that the quantities add up to 100 parts by weight.

EXAMPLES

In order to test the bleaching effect, soiled fabrics were treated withvarious bleaching solutions. The clouding of the formulations wasvisually assessed after storage for 1 week and 4 weeks at 20° C. Theincrustation of the fabrics were determined by incineration whereasyellowing of the fabrics was determined photometrically, the startingvalue of the soiled fabrics serving as standard (100%). The measurementswere carried out in a liquor with a metal ion content of 300 ppb Fe and100 ppb Mn; the water hardness was 300 ppm CaCO₃. The liquor ratio(fabric:water) was 1:50 and the exposure time 30 minutes at atemperature of 40° C. The results are set out in Table 1 below where thefigures represent percentages by weight. Compositions 1 and 2 correspondto the invention while mixtures C1 to C3 are intended for comparison.

                  TABLE 1                                                         ______________________________________                                        Bleaching effect                                                              Composition  1       2       C1    C2    C3                                   ______________________________________                                        Sodium hypochlorite                                                                        5.0     5.0     5.0   5.0   5.0                                  Sodium hydroxide                                                                           0.9     0.95    1.0   0.9   0.5                                  Sodium silicate                                                                            0.95    0.95    1.0   --    0.8                                  Sodium carbonate                                                                           --      --      0.5   1.2   1.2                                  Amine oxide phosphonic                                                                     0.1     0.1     --    0.1   --                                   acid**                                                                        Polyacrylate***                                                                            0.05    0.05    0.05  0.05  0.05                                 Appearance after                                                                           Clear   Clear   Clear Clear Cloudy                               1 week                                                                        Appearance after                                                                           Clear   Clear   Cloudy                                                                              Cloudy                                                                              Cloudy                               4 weeks                                                                       Incrustation [%-rel]                                                                       105     103     113   115   118                                  Yellowing [%-rel]                                                                          28      32      54    56    54                                   ______________________________________                                         *Modulus 2.0,                                                                 **Sequion ®,                                                              ***Norasol ® LMW 45 N (sodium salt, MW = 4,500, product of NorsoHaas)

It can be seen that the compositions according to the invention areclouding-free, even after storage, and lead to fewer lime deposits andless yellowing of the treated textiles compared with the prior-artproducts.

What is claimed is:
 1. An aqueous bleaching composition comprising:1.0to 10.0% by weight of alkali metal hypochlorite; 0.5 to 1.5% by weightof alkali metal hydroxide; 0.5 to 2% by weight of silicates; 0.01 to1.0% by weight of phosphonic acids and/or phosphonates; and 0.01 to 1.0%by weight of polyacrylic acid compounds.
 2. The composition of claim 1wherein the alkali metal hypochlorite comprises sodium hypochlorite. 3.The composition of claim 1 comprising 3 to 7% by weight of alkali metalhypochlorite.
 4. The composition of claim 3 comprising 4 to 6% by weightof alkali metal hypochlorite.
 5. The composition of claim 1 wherein thealkali metal hydroxide comprises sodium hydroxide.
 6. The composition ofclaim 1 comprising 0.7 to 1.2% by weight alkali metal hydroxide.
 7. Thecomposition of claim 1 wherein the silicates comprise sodium silicate,potassium silicate, aluminosilicate or mixtures thereof.
 8. Thecomposition of claim 1 comprising 0.8 to 1.2% of silicates.
 9. Thecomposition of claim 1 wherein the phosphonic acid or phosphonatecorresponds to the formula (I): ##STR4## wherein R¹ is an optionallyfunctionalized alkyl and/or alkenyl group containing 1 to 22 carbonatoms, and R² is hydrogen, an alkali metal, an alkaline earth metal,ammonium, alkylammonium, alkanolammonium, an optionally functionalizedalkyl and/or alkenyl radical containing 1 to 22 carbon atoms, ormixtures thereof.
 10. The composition of claim 1 comprising 0.3 to 0.7%of phosphonic acids and/or phosphonates.
 11. The composition of claim 1comprising 0.02 to 0.05% polyacrylic acid compounds.
 12. The compositionof claim 1 wherein the polyacrylic acid compounds have and averagemolecular weight in the range of from 1,000 to 10,000 daltons.
 13. Thecomposition of claim 12 wherein the polyacrylic acid compounds have andaverage molecular weight in the range of from 4,000 to 6,000 daltons.14. The composition of claim 1 comprising amine oxide phosphonic acidscorresponding to formula (II): ##STR5## wherein R³ is hydrogen, a(CH₂)_(m) (CHCH₃)_(n) NH₂ O group or an alkali metal, m is a number offrom 1 to 4, and n is 0 to
 1. 15. The composition of claim 14 comprising1 to 8% by weight of alkyl ether sulfates.
 16. The composition of claim1 further comprising 2 to 4% by weight of alkyl ether sulfates.
 17. Thecomposition of claim 14 comprising 1.5 to 6% by weight of amine oxides.18. The composition of claim 1 further comprising 1.5 to 6% by weight ofalkyl and/or alkenyl oligoglycosides.
 19. The composition of claim 1further comprising a fatty acid salt.
 20. The composition of claim 1further comprising 1 to 15% by weight of surfactants and fatty acidsalts.